1. Field of Invention
This invention relates to a simplified method of intraosseous injection for dental and other applications.
2. Background and Description of Prior Art
The benefits of intraosseous injection for dental work are well known and documented. The method consists of introducing anesthetic solution to the cancerous bone surrounding the roots of the tooth or teeth to be treated. This requires first penetrating the hard but relatively thin cortical mandibular or maxillary bone, after applying a local anesthetic to the gingival tissue of the patient's gum. Previous inventions pose serious problems in application of the method for dental practitioners, or are technically complex and expensive. For example in U.S. Pat. No 4,787,893 to Villette (1988) an extremely complicated and expensive apparatus is described. It comprises a special piece of equipment which drills a hypodermal needle into the cancellous bone and then allows anesthetic solution to be introduced through the same needle.
Apart from the expense of the apparatus there is the attendant problem of the hollow point of the hypodermal needle becoming clogged with bone fragments, thus precluding the injection of anesthetic solution. This problem has been addressed in various other inventions. For example in U.S. Pat. No. 4,944,677 to Alexandre (1990), U.S. Pat. No. 5,057,013 to Dillon et al (1991), and U.S. Pat. No. 5,173,050 also to Dillon (1992), a solid drill is used to perforate the cortical bone then withdrawn to permit the insertion of a conventional hypodermal needle to deliver the anesthetic solution. Devices of this type are in common use, but have the serious disadvantage that having withdrawn the drill the dental practitioner frequently has difficulty in locating the hole in the bone through which to insert the hypodermal needle, particularly when the gingival tissue is displaced laterally during the initial drilling. In U.S. Pat. No 5,779,708 to Cyberdent Inc. (1998) this problem is addressed by using a hollow drill, the hollow bore of which is filled by a removable stylet during drilling so as to prevent blocking with bone fragments. The stylet is subsequently removed allowing a hypodermal needle to be introduced through the hollow drill which is left in place in the patient's jaw bone for the injection of anesthetic solution. This application describes an invention which achieves the same object but in an even simpler and cheaper way.